The invention relates, generally, to electrical circuits for powering electrical equipment in industrial applications and, more particularly, to a quick disconnect switch for breaking the connection between the electrical power source and the electrical equipment.
Frequently, in industrial systems having an electrical power source connected to electrical equipment, it is necessary to perform maintenance or repair work on the electrical equipment. In order to perform this maintenance and repair work with a maximum degree of safety, the electrical connection between the power source and the equipment must be broken. In an attempt to facilitate this operation, numerous prior art switches and connectors have been developed. Typically, these switches consist of a first set of terminals connected to the electrical power source through conductive cables, a second set of terminals connected to the electrical equipment through additional electrical cables, and a sliding or rotating conductive member for selectively connecting or disconnecting the first set of terminals and the second set of terminals to thereby break or make the electrical circuit.
One shortcoming of the known switches is their susceptibility to the effects of arcing. As is well-known in the art, an arcing phenomenon occurs between the conductive member and the terminals as the gap between the conductive member and terminals narrows during opening and closing of the switch. This arcing phenomenon causes scarring on the affected surfaces such that over time the scarred connector's ability to conduct current is impaired. The electrical arc is also capable of igniting dust particles, etc, thereby causing an explosion.
A second shortcoming of the known switches is the need for a separate enclosure to isolate the switch from the surrounding environment in the event that the arcing at the switch causes an explosion. One such enclosure is disclosed in U.S. Pat. No. 4,620,061. The present invention eliminates the need for a separate explosion proof enclosure because the contact elements of the switch are located within an explosion proof housing that is designed as part of the switch.
Switches used in this capacity must have a high degree of reliability because the potential for harm from a faulty switch is great. Moreover, the switches must be dependable so as to be able to perform reliably over an extended period of time. The switch should be simple and inexpensive to manufacture and install so as to make its use practicable. The switches must also minimize arcing and the effects thereof such as scarring of the electrical contacts and risk of explosion. Moreover, the apparatus used to break the connection should operate as quickly and easily as possible to minimize the idle time of the equipment.